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Proceedings Paper

A 12-bit 500KSPS cyclic ADC for CMOS image sensor
Author(s): Zhaohan Li; Gengyun Wang; Leli Peng; Cheng Ma; Yuchun Chang
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Paper Abstract

At present, single-slope analog-to-digital convertor (ADC) is widely used in the readout circuits of CMOS image sensor (CIS) while its main drawback is the high demand for the system clock frequency. The more pixels and higher ADC resolution the image sensor system needs, the higher system clock frequency is required. To overcome this problem in high dynamic range CIS system, this paper presents a 12-bit 500-KS/s cyclic ADC, in which the system clock frequency is 5MHz. Therefore, comparing with the system frequency of 2N×fS for the single-slope ADC, where fS, N is the sampling frequency and resolution, respectively, the higher ADC resolution doesn’t need the higher system clock frequency. With 0.18μm CMOS process, the circuit layout is realized and occupies an area of 8μm×374μm. Post simulation results show that Signal-to-Noise-and-Distortion-Ratio (SNDR) and Efficient Number of Bit (ENOB) reaches 63.7dB and 10.3bit, respectively.

Paper Details

Date Published: 13 March 2015
PDF: 7 pages
Proc. SPIE 9403, Image Sensors and Imaging Systems 2015, 94030K (13 March 2015); doi: 10.1117/12.2083269
Show Author Affiliations
Zhaohan Li, Jilin Univ. (China)
Gengyun Wang, Jilin Univ. (China)
Leli Peng, Jilin Univ. (China)
Cheng Ma, Jilin Univ. (China)
Yuchun Chang, Jilin Univ. (China)

Published in SPIE Proceedings Vol. 9403:
Image Sensors and Imaging Systems 2015
Ralf Widenhorn; Antoine Dupret, Editor(s)

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